D-mannitol is the D-enantiomer of mannitol. It has a role as an osmotic diuretic, a sweetening agent, an antiglaucoma drug, a metabolite, an allergen, a hapten, a food bulking agent, a food anticaking agent, a food humectant, a food stabiliser, a food thickening agent, an Escherichia coli metabolite and a member of compatible osmolytes.